MORE THAN 50 years ago, A. J. Liebling, the greatest writer of fights who ever lived, wrote that the one thing all fight guys can agree on is that boxing used to be better.

For instance, 28 years ago today, no less an authority than Jack Dempsey had this to say about a man who had just defended the undisputed world’s heavyweight championship:

“He’s the best we have right now. Let’s leave it at that.”

Dempsey, who a half-century earlier had been knocked clear out of the ring in the Polo Grounds by Luis Angel Firpo but climbed back in to win, was talking about Joe Frazier, who had just beaten Muhammad Ali.

Today, that bout is considered the gold standard by which all other heavyweight title fights are measured, but to Dempsey, it was just further evidence of how far the game had fallen since the 1920s, considered the Golden Age of Boxing.

And he was probably right, since Dempsey’s trip home from the Garden that night wasslightly delayed because he had to knock out two young punks who had the nerve to try to mug him in a taxicab.

How many 76-year-olds would have the guts to do that today? How many 36-year-olds, for that matter?

Yes, in its relentless pursuit of civilization, the world has certainly gotten softer.

Why, we’ve even got people trying to convince us that the fight Saturday night at the Garden between Evander Holyfield and Lennox Lewis could be another – tsk, tsk – Ali-Frazier I!

Consider that more a commentary on the sad state of boxing than on the magnitude of the matchup.

But as the Manassa Mauler so astutely observed on March 8, 1971, Holyfield-Lewis is the best we have right now.

Let’s leave it at that.

No doubt, this long-awaited match to (temporarily) unify the heavyweight title for the first time in seven years is the best the division has to offer, and probably the best event the Garden has showcased in, oh, 28 years or so.

That includes basketball games, hockey games, wrestling matches, the Westminster Kennel Club dog show and the Muppet Babies on Ice.

There is nothing like Fight Night at the Garden, and there are no fight nights like a heavyweight title fight night.

But will Holyfield-Lewis be the greatest fight of all time, or even a rival to Ali-Frazier I, the greatest fight people too young to remember Dempsey-Firpo had ever seen?

Don’t bet on it.

For one thing, it takes two great fighters to make one great fight.

Saturday night, you’ve got one great fighter and one great big disappointment.

Say what you will about the state of boxing and the quality of the heavyweight division these days, and chances are it will be true.

And yet, after Muhammad Ali and Joe Louis, I can’t find another heavyweight in boxing history with a better record against the contenders of his era than Evander Holyfield.

And I can’t think of another heavyweight in an era who has done less with more than Lennox Lewis. He may have three passports but he has no credentials as an important heavyweight. A win over Holyfield would be the first in his record truly worth bragging about. Still, within the context of the day, a match between Holyfield and Lewis is about as good as it gets in heavyweight boxing.

It may turn out to be a very competitive and even electrifying fight for as long as it lasts, because the number of bad fights Holyfield has been in can be counted on the fingers of a boxing glove.

But to equate it with a fight that not only matched two of the sport’s all-time greats but also ushered in a new era of money and glamor and visibility to heavyweight boxing seems not only a bit overstated, but also naive, and even disrespectful.

The difference between Holyfield-Lewis and Ali-Frazier is simple.

Twenty-eight years ago, nobody was sure who was going to win the latter, but six days in advance, I am certain of who will win the former.

In fact, the only thing that can beat Evander Holyfield is his own overconfidence. I have never heard him show as much disrespect for an opponent as he has shown for Lewis over the past month.

Then again, he can analyze fight tapes and interpret records and, most importantly, sense what is in a man’s heart and soul as well as any of us, and probably better.

When the rest of the world was predicting his death, Holyfield had no doubt he would beat Mike Tyson.

He seems to have even less doubt he will beat Lewis, only this time, the rest of the world appears to be with him.

Holyfield is unquestionably a great fighter, an accolade he earned the only way such accolades can be earned: By winning great fights.

Dwight Qawi, Michael Dokes, George Foreman, Riddick Bowe (the second time) and Mike Tyson (the first time) gave Holyfield great battles that he eventually won.

But Lewis has so far been a great big bust.

Yesterday, I asked Emanuel Steward, Lewis’ trainer, to name one Lewis performance that he felt provided evidence that Lewis could beat Holyfield.

The fights he named were Lewis’ KOs over Razor Ruddock, Tommy Morrison and Andrew Golota.

And on paper, those wins look impressive – Lewis stopped Ruddock in two rounds, Morrison in seven, Golota in one.

But fights are won on canvas, not paper, and are fought by human beings, not cardboard cutouts.

And not one of those three fights can stand up to any kind of scrutiny.

For instance, Ruddock was coming off two losses to Tyson, the second of which left him with the kind of injuries from which fighters never fully recover – a broken cheekbone and jaw.

For the Lewis fight, Ruddock had marital woes, managerial woes, training woes and probably, the beginnings of the drug problems that would sideline him the next four years. He was ripe to be plucked that night at Earl’s Court, and Lewis plucked him.

Same with Morrison, who had already been exposed by Ray Mercer and Michael Bentt, both of whom not only knocked Morrison out, but nearly killed him. Lewis did not improve on either man’s performance and a few months later, Morrison tested positive for HIV.

Which brings us to Golota, would-be two-time conqueror of Riddick Bowe if not for his unfortunate habit of hitting below the belt, oh, a dozen or so times in the course of a fight.

But Golota’s Dirty Little Secret was not that he was a dirty fighter – anyone could see that from the last row of the Garden – but that on every fight night, he had to be virtually dragged into the ring.

His trainer, Lou Duva, admitted as much after Golota’s non-performance against Lewis, which was belatedly, and fraudulently, blamed on the administering of a pain-killing injection just before the fight.

Truth was, Golota was paralyzed with fear. Steward, a great trainer and a greater tactician, knew that and sent Lewis out blazing for a first-round KO.

If these are the fights the Lewis camp is basing its confidence on, expect a blowout.